#include <iostream>
#include <algorithm>
using namespace std;

const int N = 1010;
int f[N], a[N];
int n;
int main()
{
    cin >> n;
    int res = 0;
    for (int i = 1; i <= n; ++i)
        cin >> a[i];
    for (int i = 1; i <= n; ++i)
    {
        f[i] = a[i];
        for (int j = 1; j < i; ++j)
            if (a[j] < a[i])
                f[i] = max(f[i], f[j] + a[i]);
        res = max(res, f[i]);
    }
    cout << res << endl;
    return 0;
}